It is planned to carry out research on the kinetics and equilibria of reactions of Schiff bases derived from pyridoxal and alpha amino acids or pyridoxamine and alpha keto acids. Other forms of vitamin B6, such as pyridoxal phosphate and pyridoxamine phosphate may also be studied, and the reactions will be investigated as a function of pH and in the presence and absence of a number of catalytic metal ions, such as those of A1(III), Ga(III), and Zn(II). Studies now underway that will be further investigated during the next grant year include: (1) dealdolation reactions (models for threonine aldolase), (2) the elimination of electronegative substituents from the beta-positions of amino acids, and (3) the decarboxylation of alpha-amino and alpha-keto acids. A new phase of the work proposed for the next year is the study of reaction kinetics and equilibria in systems that undergo the elimination of electronegative substituents from the gamma-position of alpha amino acids, and associated beta-proton exchange reactions. These studies are considered important since there have been very few reports on this type of reaction, and because they are important in bioloical processes. The equilibrium and kinetic studies on the systems described above will be employed to determine reaction pathways, elucidate reaction mechanisms, and demonstrate constitutional requirements of the substrate for reactivity.